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V-230290

CAT II (Medium)

The RHEL 8 SSH daemon must not allow authentication using known host’s authentication.

Rule ID

SV-230290r1069302_rule

STIG

Red Hat Enterprise Linux 8 Security Technical Implementation Guide

Version

V2R7

CCIs

CCI-000366

Discussion

Configuring this setting for the SSH daemon provides additional assurance that remote logon via SSH will require a password, even in the event of misconfiguration elsewhere.

Check Content

Verify the SSH daemon does not allow authentication using known host’s authentication with the following command:

$ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*ignoreuserknownhosts'

/etc/ssh/sshd_config:IgnoreUserKnownHosts yes

If the value is returned as "no", the returned line is commented out, or no output is returned, this is a finding.

If conflicting results are returned, this is a finding.

Fix Text

Configure the SSH daemon to not allow authentication using known host’s authentication.

Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes":

IgnoreUserKnownHosts yes

The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command:

$ sudo systemctl restart sshd.service